The Multi-Barrier Approach to Safe Water

* water hygiene

Safe Storage

Treatment

Disinfection Filtration Sedimentation

Each step in the process incrementally reduces risks.

A multi-barrier approach is the best way to reduce the risk of drinking unsafe water.

50%

More often than not, people focus on a particular technology that is directed towards one step, rather than considering the whole water treatment process. The entire process is essential to provide the best water quality possible for improved health.

What is the best technology? There is no “silver bullet” technology. Context-appropriate solutions take into account the local water situation, communities’ needs and preferences, economic factors, availability of local skills, and local or national regulations. It’s not just about the technology - it’s mostly how it is implemented. We need to understand what has or hasn't worked and why.

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Households do a lot of work to collect, transport and treat their drinking water. After the water is treated, it needs to be handled and stored properly to keep it safe. Recontamination of safe drinking water is a significant issue.

Household water treatment (also called point of use) follows the same basic water treatment process as community systems. The main difference is the scale of the systems. HWTS is primarily focused on removing pathogens - the biggest health threat.

sanitation

100% 90%

to inactivate

any remaining pathogens

to remove

smaller particles and often >90% of

pathogens

to remove

larger particles and up to >50% of

pathogens

Source Protection

Household Water Treatment & Safe Storage (HWTS)

DISINFECT FILTER

SEDIMENT

Safe Storage

Treatment

Hygiene Hygiene refers to the conditions and practices that help to maintain health and prevent the spread of diseases.

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STEPS to improve water quality

Hygiene promotion: Systematic approaches to encourage the widespread adoption of safe hygiene practices to reduce diarrheal and other water- and sanitation-related diseases. There are many factors that motivate changes in behaviour. These may or may not be related to knowledge of the health consequences of poor hygiene. Individual behaviour and a hygienic environment

are important to protect individual health.

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Sanitation is the safe management of human excreta. The objective is to protect public health by protecting the water source, preventing excreta from contaminating the environment and breaking the cycle of disease.

Sanitation

Sanitation system: Also called a sanitation chain, value chain or sanitation service chain. A collection of technologies that deals with human excreta, from the time it is generated until it is used or disposed of safely. It is a general term for both sewered and non-sewered sanitation systems.

User Interface

Excreta Storage

Treatment Use or

Disposal

Treatment Sewer

Fecal Sludge Management (FSM)

Use or Disposal

Sewered Sanitation System

Fecal sludge: Excreta from an on-site sanitation technology that may also contain used water, anal cleansing materials, and solid waste.

Treatment: Any process to inactivate pathogens, stabilize, dewater, or manage nutrients in fecal sludge.

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On-site sanitation technology: Included in the first two components of a sanitation system: user interface and excreta storage. Excreta is collected and stored where it is produced (for example, a pit latrine, septic tank, aqua privy, and non-sewered public toilets).

Fecal sludge management: Includes the emptying, transport, treatment, and safe use or disposal of fecal sludge from an on-site sanitation technology.

Online WASH Resources Find more definitions at

cawst.org/WASHglossary

Find over 3,000 WASH education & training resources at

cawst.org/resources

Get support today from our Technical & Education Advisors at

support@cawst.org

References at cawst.org/miniWASHGuide

Emptying & Transport

Non-sewered system: Also called on-plot or on-site sanitation. A sanitation system in which excreta and used water are collected and stored on the location where it is produced. Often, the fecal sludge has to be transported off-site for treatment, use or disposal.

Non-Sewered Sanitation System

Wastewater: Used water from any combination of domestic, industrial, commercial or agricultural activities, surface runoff (stormwater), and any sewer inflow (infiltration). Wastewater can be managed on-site or off-site. Wastewater managed off-site is often called sewage.

User Interface

Sewered system: Also called a sewer system, sewerage system, sewers, connected sanitation, and networked sanitation. A sanitation system that transports wastewater through a pipe network (like a simplified sewer or conventional sewer) to another location for treatment, use or discharge. This includes centralized systems and decentralized wastewater treatment systems.

Sanitation system illustrations by Bill and Melinda Gates Foundation (BMGF); CC by 2.0